Knife-carrier for paper cutting machines



Jan. 2, 1934. K. STEGMANN 1,941,957

KNIFE CARRIER FOR PAPER CUTTING MACHINES Filed July 12 1930 E a/ 7 a! Patented Jan. 2, 1934 UNITED STATES PATENT OFFICE KNIFE-CARRIER FOR PAPER CUTTING MACHINES Application July 12, 1930. Serial No. 467,435, and in Germany July 16, 1929 2 Claims.

This invention has reference to improvements in cutting machines for paper, card board and the like and it relates particularly to machines of this description in which the knife carrier is pro- 5 vided with double face for the mounting of the cutting blades. In the type of paper cutting machines and the like now usually employed the knife carrier is provided with the so-called double face structure for the mounting of the knives, inasmuch as by this means the knives or blades may be more advantageously utilized than in the case of knife carriers provided with one operating face only and requiring a considerably wider bearing surface of the knife on its corresponding carrier in view of the fact that the fastening screws cannot be forced sufliciently downwards in order to prevent the head of the screw from projecting beyond the outlines of the knife carrier. With such double face carriers there is however the difficulty that in the case of very considerably ground off blades it becomes impossible to effect a severing cut when working on piles of usual height. The action of the blades on such piles presents the difliculty that the knife carrier becomes seated on the pile, thereby producing injury to the machine, so that machines of this kind and with ground ofi knives in producing a severing or separating out can only be operated on piles of small height, and therefore only a fraction of the efficiency of the machine can be utilized.

These difliculties are avoided according to this invention by disposing between the knife carrier and the knife an upwardly inclined sheet of metal or a piece of metal arranged in an upwardly inclined path, which, upon the insertion of the knife into the pile acts to feed the ground off portion forward, so as to eliminate the liability of the knife carrier becoming seated upon the pile and to make it possible thereby to effect the cutting of even relatively high piles by means of decidedly ground oil and used up knives. There is the additional advantage that with this kind of arrangement there is the possibility of producing a further grinding off of the knives, so that the duration of the knives is increased.

The invention will be more. particularly de scribed by reference to the accompanying drawing showing by way of exemplification a form of knife carrier embodying the invention.

Fig. 1 is a sectional view of the knife carrier with a knife secured thereto provided with the improvement according to this invention. Fig. 2 is a front elevation of the device according to Fig. 1, and Fig. 3 illustrates the manner of connecting the invention to the knife carrier.

In the devices as heretofore employed the attempt of producing severing cuts on piles of rather considerable height by means of comparatively ground off and consequently rather short knives was liable to produce injuries to the ma chine because the knife carrier 4 was liable to' become seated upon the pile with no possibility of moving it sideways, and this difliculty was the cause of frequent injuries and breaking down of the machine. This is due to the fact that the line a--bc presents a number of breaks and cannot be converted into a sufliciently straight line, because the fastening screws 3 should be arranged as near as possible to the lower edge of the knife carrier, in order to rigidly secure the knife in position and in view of the fact that the heads of these screws should not project beyond the outline of the knife carrier. Moreover, the exchanging of knives with such construction is very diflicult.

In accordance with this invention a piece of sheet metal 1 is secured by means of screws 2 to the knife carrier and this plate or sheet 1 is so arranged that its free end will bear against the knife under an angle of for instance at least 40 degrees which is sufiiciently flat to cause the cut off material to be pushed aside without appreciable resistance and without injury to the material. This plate 1 may preferably comprise a piece of-polished sheet of brass which covers up the sockets or holes forthe knife screws 3. But it should be understood that the plate may also be formed of polished steel or the like. The sheet 1 or its attachment is so constructed that the sheet is always applied on the knife and thus assures a good removal ofthe paper. In Fig. 1 the position of the sheet with a very much ground 01f knife is shown in solid lines, while the dotted lines show the position which the sheet assumes when the knife is not ground down and has, for example, the width shown in dotted lines. The screws 2 which" serve for securing the piece of sheet metal 1 to the knife carrier 4 are engaged with the turnedover edge 2' of the plate 1 which serve for reinforcing the plate 1. The screws 2 may be securely connected to the plate 1 by the turnedover edge, so that they cannot be lost, when the plate is detached.

It should be noted that the invention is not restricted to the particular exemplification herein shown and described norto the relative arrangement of the .parts and that variations and jacent the edge thereof.

3 In. a device of the class described a blade support having a straight face and an inclined face, a blade detachably and interchangeably secured to the straight face of said support, a metal plate secured to the inclined face of said support and said plate cooperating with said blade and being inclined to said blade at any position of said plate.

KARL STEGMANN. 

